Tracking Passivation and Cation Flux at Incipient Solid‐Electrolyte Interphases on Multi‐Layer Graphene using High Resolution Scanning Electrochemical Microscopy

Abstract

The solid electrolyte interphase (SEI) is a dynamic, electronically insulating film that forms on the negative electrode of Li+ batteries (LIBs) and enables ion movement to/from the interface while preventing electrolyte breakdown. However, there is limited comparative understanding of LIB SEIs with respect to those formed on Na+ and K+ electrolytes for emerging battery concepts. We used scanning electrochemical microscopy (SECM) for the in situ interfacial analysis of incipient SEIs in Li+, K+ and Na+ electrolytes formed on multi‐layer graphene. Feedback images using 300 nm SECM probes and ion‐sensitive measurements indicated a superior passivation and highest cation flux for a Li+‐SEI in contrast to Na+ and K+‐SEIs. Ex situ X‐ray photoelectron spectroscopy indicated significant fluoride formation for only Li+ and Na+‐SEIs, enabling correlation to in situ SECM measurements. While SEI chemistry remains complex, these electroanalytical methods reveal links between chemical variables and the interfacial properties of materials for energy storage.

Regulating the interfacial charge separation between MoS2QDs and sea-urchin graphitic carbon nitride for deep photodegradation of tetracycline under visible light

“…1a and b, which is consistent with other observations. 24,25 The microstructure of SUCN was similar to that of sea urchin, with numerous pointed cone-shaped nanofibers sprouting on its main structure (Fig. 1c and d).…”

In situ Observation of Evolving H2 and Solid Electrolyte Interphase Development at Potassium Insertion Materials within Highly Concentrated Aqueous Electrolytes

“…These curves fit to typical approach curve models (Figure S12) indicating k eff of � 2×10 À 4 cm/s, significantly slower than k eff measured at conductive substrates in aqueous media and in line with measurements at SEI found on Li metal and graphitic electrodes after cycling. [35,36] We emphasize the actual rates are likely slower, but this result clearly suggests the formation of a passivating SEI structure in our 55 mol/kg K(FSA) 0.6 (OTf) 0.4 electrolyte during cycling. Hard x-ray photoelectron spectroscopy measurements in our previous report suggested that various structures deposit on the PTCDI surface after cycling including F-and S-containing components.…”

Fluorosulfonamide-type electrolyte additives for long-life K-ion batteries

“…It is well-known that the electrolyte composition can impact the formation and properties of the SEI. 1,[57][58][59] To avoid possible alteration of the SEI by the presence of K metal, 60 we utilized graphitekMn-PB full cells. Aer 10 cycles at 0.1C, we quickly disassembled the cells inside a glovebox, rinsed the graphite electrodes using fresh DEC and allowed them to dry in the glovebox.…”